This invention relates to independently addressable semiconductor diode lasers, and, more particularly, to low-loss passive waveguides integrally connected to the localized optical gain active regions of the semiconductor diode lasers.
Monolithic arrays of independently addressable semiconductor diode lasers are the optical sources of choice for high-speed, high-resolution xerographic printers and optical storage systems.
However, independently addressable laser arrays within a monolithic semiconductor structure present several problems.
Increasing the number of laser emitters within the monolithic semiconductor structure decreases the spacing between adjacent laser emitters. This decreased spacing may cause crosstalk between adjacent laser emitters.
The area on the surface of the monolithic semiconductor structure is limited for the number of contacts for the emitters and may require complicated crossover contacting patterns.
Since the area on the surface of the monolithic semiconductor structure is limited and since the volume within the monolithic semiconductor structure is also limited, the addition of detectors to monitor the level of emitted light from each semiconductor diode laser will further decrease the number of contacts on the surface available for laser emitters within the monolithic semiconductor structure.
It is difficult to configure the optical gain active regions of the semiconductor diode lasers within the monolithic semiconductor structure so each will emit light at a different wavelength or so adjacent emitters will emit light to partially overlap without introducing optical interference.
It is an object of this invention to provide an increased density of independently addressable semiconductor diode laser emitters within a monolithic semiconductor structure.
It is another object of this invention to reduce crosstalk between adjacent semiconductor diode laser emitters within a monolithic semiconductor structure.
It is yet another object of this invention to provide a separately addressable monitoring detector incorporated on the axis of each semiconductor diode laser emitter with inherent discrimination against light spontaneously emitted by the emitter's optical gain active region.
It is another object of this invention to provide semiconductor diode laser emitters within a monolithic semiconductor structure to emit light at a different wavelength or adjacent laser emitters to emit light to partially overlap without introducing optical interference.